1. Field of the Invention
The present invention relates to a sleeping mattress, and more particularly to a sleeping mattress provided with a hard core member therein together with a plurality of permanent magnets disposed in a body-supporting surface of the sleeping mattress.
2. Description of the Prior Art
A sleeping mattress of this kind is disclosed, for example, in U.S. Pat. No. 4,509,219. In such a conventional sleeping mattress, a plurality of semi-spherical projections are formed in a surface of a board-like fiber layer which is a compression layer of fibers such as natural vegetable fibers like palm fibers or of fibers such as synthetic fibers, in a top concave portion of each of which projections a small magnet piece is embedded. These semi-spherical projections are covered with a sheet made of suitable materials such as urethane foam and the like. On the other hand, a structural frame constructed of flexible wires such as steel wires is provided inside the above fiber layer to form a core member of the sleeping mattress.
However, the core member of the above conventional sleeping mattress is cumbersome in assembling of the sleeping mattress because, in order to hold the shape of the sleeping mattress well, the structural frame constructed of the flexible wires such as steel wires must be inserted into the compression fiber layer. In addition, such structural frame increases material cost as well as production cost in manufacturing thereof, and also considerably increases the weight of the sleeping mattress to impair easiness in use thereof. Further, due to the presence of such structural frame, the magnetic effect of the permanent magnets of the conventional sleeping mattress does not serve well at deeper parts of the user's body.